Power conversion interface with harmonic suppression for a DC grid and single‐phase utility

Abstract

This study proposes a power conversion interface for a DC grid and a single-phase utility. The proposed power conversion interface is configured using an interleaved AC–DC power converter and a DC hybrid power filter. The interleaved AC–DC power converter controls the real power between the DC grid and the single-phase utility in both directions. The interleaved AC–DC power converter can effectively reduce the high-frequency harmonic currents at both the AC side and DC side. A new current-sharing control method is used to equalise the currents in the interleaved power-electronic arms using only one current sensor in the interleaved AC–DC power converter. The DC hybrid power filter is connected between the DC bus of the interleaved AC–DC power converter and the DC grid. The DC hybrid power filter is controlled to be operated as a virtual low-frequency AC resistor connected to the DC grid in series and the low-frequency harmonic for the DC input current of the interleaved AC–DC power converter is suppressed. Accordingly, the problems of harmonic currents for a power conversion interface used between the DC grid and the single-phase utility are attenuated. A hardware prototype is developed to verify the performance of the proposed power conversion interface.